Like the moving cities it depicts, Reeve's debut novel is a staggering feat of engineering, a brilliant construction that offers new wonders at every turn. In the Europe of the future, the great cities have uprooted themselves from the Earth and donned wheels; roving the Hunting Ground that was once Europe, cities literally devour one another as part of a new social construct called Municipal Darwinism. The mighty city of London, in danger of running out of "prey," looks toward the east, where an enormous wall protects the static cities of the Anti-Traction League—the "heretics" who have chosen the barbaric practice of living on the bare earth. But London's mad Lord Mayor develops a plan to get through the wall: he resurrects a vicious and ancient technology, a post–20th-century update of the nuclear bomb, all the more horrible with time and refinement, and mounts it in the dome of St. Paul's Cathedral. Against this wildly original backdrop plays the story of Tom Natsworthy, a young Apprentice Historian who helps mine the museum vaults of the juggernaut London. Tom becomes embroiled with his idol, the elder Historian Valentine, and also with the scarred girl Hester who owes Valentine a debt of vengeance. Reeve's prose is sweeping and cinematic, his ideas bold and effortless; he deftly weaves in social commentary on the perils of both war and consumerism, and presents the calamities that can result from poverty and extreme wealth occupying the same quarters. Ages 12-up. (Nov.)